Electronics technology has proliferated with the advent of inexpensive and high performance integrated circuits, including communication transceivers, microprocessors, and memory. As a result, complex electronic systems, such as personal computers and cellular telephones have become widely held consumer goods.
Integrated circuits are fabricated with multiple processing steps. Integrated circuits are often fabricated with one or more device types including diodes, capacitors, and different varieties of transistors. These devices often have microscopic features that can only be manufactured with critical processing steps that require careful alignment of equipment used to build the devices. The critical processing steps are expensive because they must be accomplished with costly and sophisticated equipment, and experienced operators. When a processing step, particularly a critical processing step, is unsuccessful, the device and integrated circuit may fail. As a result, fabrication yields decrease. Therefore, a process with a diminished number of critical processing steps to reduce production costs is desirable.
Further, prior art typically uses Buried Contacts (BC) that connect a first conductor to substrate active area. The BC process however is a lower yielding process than the self aligned contacts described herein. In addition, BC's require full enclosure by the first conductor which requires additional area, thereby increasing the cell size.
Additionally, it is preferable to reduce the cross-sectional area of devices and integrated circuits. When device and integrated circuit cross-sectional area is reduced, more devices and integrated circuits can be produced on a single substrate. As a result, device and integrated circuit fabrication costs decrease. Therefore, a low cost process with fewer critical processing steps for fabricating devices and integrated circuits with reduced cross-sectional areas is desirable. An integrated circuit is also needed which electrically couples substrate active area with a conductor without the need for a buried contact.